Centrifugal separator



Ap 3, 1934. J. KLOTZ CENTRIFUGAL sEPARAToR Filed Nov. 15, 1932 2Sheets-Sheet l April 3, 1934. 1 KLo-rz y 1,953,237

CENTRIFUGAL sEPARAToR Filed NOV. l5, '195g 2 Sheets-5h68?. 2

Patented Apr. 3, 1934 1,953,237 CENTRIFUGAL snrAnA'ron Josef Klotz,Heidenheim, Wurttemberg, Germany, assigner to American Voith ContactCompany, Inc., New York, N. Y., a corporation of New York ApplicationNovember 15, 1932, Serial No. 642,767 In Germany September 21, 1931 6Claims.

This invention relates to centrifugal separators,

and has for its general object and purpose to provide certainimprovements in machines of the type wherein the centrifuging means isarranged within a fixed cylindrical screen for rotation about ahorizontal axis, and which is particularly designed and intended for usein the screening or separation of worthless materials from ground woodpulp, chemical pulp, etc.

It is one of the important objects of the present invention to providemeans whereby the screened stock is discharged from the base or bottomof the machine, while at the same time the required pressure upon thematerial within the machine is adequately maintained.

Centrifugal separators of this character are generally known and aredistinguished from other types by the fact that the feed trough for theunscreened stock together with the discharge troughs for the screenedstock and the worthless residue, have heretofore been located at acertain level or elevation above the machine and connected with theinterior thereof through closed pipes or conduits. Therefore, it isevident that the pressure existing within the machine is dependent uponthe static pressure head of the unscreened stock in the feed trough andin the discharge troughs. The prior art construction also necessitatesthe arrangement of the discharge trough for the screened stock above themachine which, in many cases, results in unfavorable room conditions.This disadvantage is overcome by the present invention.

I attain this object in one embodiment of the invention by arrangingaround the cylindrical screen plate two spaced cylinders, the inner oneof which is provided with an opening at its top through which thescreened stock is ejected, while the outer cylinder has a bottom openingthrough which the stock is discharged from the space between saidcylinders into the collection trough.

It is also another important object of the invention to provide simpleand efficiently operating means whereby a uniform distribution of thestock from the inlet or feed trough over the entire surface area of thecylindrical screen is obtained. Heretofore, the incoming stoel:following the horizontal axis of the inlet connection, owing to theforce of gravity, distributed itself unevenly over the cylindricalscreen plate. Thus mass accumulations of the stock at certain points, asat the bottom of the screen cylinder, operated to prevent the uniformscreening of the stock. Attempts have been made to overcome thisobjection by delivering the stock uniformly in spaced jets over thescreen plate. It was found, however, that these stock jets wereinterrupted by the rotating runner blades within the screen cylinder,and resulted in a very appreciable increase in power consumption.Further, the interruption of the stock jets decreased the effectivenesswith which they were distributed over the screen plate and resulted onlyin the whirling of the stock by the runner blades. Thus, the capacity ofthe screen was appreciably decreased. In other designs, the stock feedinlet has been provided with stationary guide vanes and the runner wheelhub with short ribs for guiding the stock into the screening orseparating zone. Such stationary guide vanes, however, offer a verysubstantial resistance to the flow of the stock current whichnecessitates a higher static feed pressure with a corresponding increasein stock pressure within the screen. In order to obtain this high staticpressure, it is therefore necessary to arrange the feed and dischargetroughs at a very high elevation above the separating screen.

My present invention overcomes these disadvantages by the provision ofmeans whereby the entire stock current Within the discharge end of thefeed connection is rotated before entering the screen cylinder, and asit enters, the cylinder is diverted from an axial to a radial flow,thereby effecting its uniform distribution over the surface of thecylinder.

With the above and other objects in view, the invention consists in theimproved centrifugal separator, and in the form, construction andarrangement of its several parts as will be hereinafter more fullydescribed, illustrated in the accompanying drawings, and subsequentlyincorporated in the subjoined claims.

In the drawing wherein I have disclosed one simple and practicalembodiment of the invention, and in which similar reference charactersdesignate corresponding parts throughout the several views,-

Figure 1 is a vertical sectionalview through one form of apparatusembodying certain features of my present invention;

Fig. 2 is a sectional View taken substantially on the line II-II of Fig.1;

Fig. 3 is a central vertical section similar to Fig. 2 and illustratinganother important feature of the invention; and

Fig. i is a detail sectional View taken substantially on the line IIT-IVof Fig. 3.

Referring in detail to the drawings, the runner wheel a is fixed upon ashaft al extending. 1

on the end wall d communicates and leads to the through a feed inletopening in one end wall b of a suitable housing with which one end ofthe stock feed elbow b1 is suitably connected. One end of shaft alextending through the elbow b1 is journalled in a stuiiing box ,b2 andhas secured thereto a belt wheel or other suitable drive connection withthe source of power.

The opposite end of the shaft a1 is journalled in the stuing box d2 onthe other end wall of the housing.

The cylindrical screen c within the housing is suitably mounted andsupported in a fixed position upon the housing walls b and d, saidscreen being entirely open at its opposite ends. With one end of thisscreen and at the upper side thereof, a vertically extending dischargeconduit d1 residue receiving trough indicatedat 1c.

The runner wheel a within the screen cylinder c includes a hub a2carrying any desirable number of runner blades a3 extending radiallyfrom the hub and having their outer edges positioned in closely parallelrelation to the inner surface of the cylindrical screen c. Thus, bymeans of these blades, the stock is centrifugally thrown outwardly andkept in constant motion upon the inner surface of the cylindrical screenplate.V The stock is supplied through the feed elbow b1 from a suitabletrough or hopper indicated at i.

n The end walls b and d are rigidly connected with each other below andabove the screen c by the plates d3, d4 respectively. The bottom plated3 forms part of an inner cylinder concentrically Vspaced from thescreen c and which also includes the sections e1, e2. These cylindersections have their upper edges transversely spaced apart and arerigidly xed between the end walls A b and d by any suitable means asindicated at f e3. ,There is thus provided an opening f at the whichopens into the trough Z. Thus, the screened stock passing through theopening f into the space between the inner and outer cylinders of the'screen housing is discharged at the bottom of the machinei.

The position of opening f determines the static pressure under which thescreening or separating action is effected. Practical tests have shownthat in order to obtain the desired result, this pressure need not bevery great, so that if the inner housing cylinder is arranged at thecustomary distance from vthe cylinder screen, the proper screening ofthe stock under pressure with the screening space always completelyfilled with the stock, will be fully realized. By the discharge of thescreened stock at the bottom of the machine from the space between saidinner and outer cylinders, in distinction to prior art machines of asimilar type, it is not necessary to locate the receiving trough for thedischarged stock, as well as Ythe feed trough and the residue receivingtrough above the level of the screen cylinder. Therefore, it is evidentthat the new construction constitutes a more compact and simplearrangement and results in a substantial saving in space.

In Fig. 3 of the drawings, I have illustrated an additional feature ofthe invention not shown in Fig. 1, whereby a uniform distribution of theunscreened stock over the entire surface area of the screening cylinderis obtained. As therein shown, the runner wheel hub a2 has a cone shapedend portion extending into the outlet end of the feed elbow b1 andmerging into an annular flange or disc a5. This conical end of the wheelhub is provided with a plurality of blades a4 projecting from thesurface thereof and extending fromthe shaft a1 to the periphery of theflange a5, the cuter end edges of said blades being disposed closelyadjacent to the surface of the cylinder, and preferably at the samedistance from shaft al as the edges of the blades a3. The-blades a4 maybe the same in number as the blades a3 and disposed in the same radialplanes as the latter blades or they may be of greater or less numberthan the blades a3.

It will be evident from the above description that as the unscreenedstock flows into the horizontal discharge end of the elbow b1, it iscaught or seized by the blades a4 and forced outwardly thereby. Thepenetration of these blades into the end of the elbow creates a certainvacuum therein inducing a flow of the stock particles adjacent the wallsof the elbow towards the shaft a1. Since these blades a4 extend over theconical end of the hub to the screen cylinder, a uniform distri-- butionof the rotating mass of stock entering the screen cylinder over the huba to the inner surface of said cylinder is effected. The greater amountof this stock not passing immediately through the screen cylinder isforced in an axial direction inwardly through the space between theperiphery of the flange a5 and the wall of the cylinder. Therefore, itis clear that under the pressure of the column of stock in the inletelbow b1 and trough i, an annular body of the stock of substantiallyuniform thickness is distributed over the entire inner surface area ofthe screen cylinder, and is kept in constant rotation relative to saidcylinder by the runner wheel blades a3. Therefore these blades will havefull effect upon the stock body to force the same through the wall ofsaid screen cylinder.

It will further be seen from the above description that there is nopossibility that owing to relative differences in the speed of movementof the stock and of the rotating blades a3, the screening efficiency ofthe machine will be disadvantageously affected. Since the deviceeifectually prevents the accumulation of large quantities of thestock atseparated points on the inner surface of the screen, clogging of theperforations in the screen plate is obviated. Therefore, a machineequipped with my present improvements, while of very large capacity andoutput of screened stock, may be operated with the consumption of lesspower than other machines of this type, and appreciable economy inoperation also results from the fact that it becomes unnecessaryperiodically to stop the operation of the machine for the purpose ofcleaning the screen cylinder plate.

From the above description considered in connection with theaccompanying drawings, the construction, manner of operation and severaladvantages of the disclosed embodiment of the invention will be clearlyand fully understood. It will be appreciated that I have produced acentrifugal separator of this type, which is very compact in thearrangement of its several parts, and may therefore be produced at lowmanufacturing cost, while it may be operated at very high speeds andwith maximum eficiency. I have herein referred to a practical embodimentof the essential features of my invention which, however, might also beproduced in various other alternative structural forms to accomplishsubstantially the same results. It is therefore to be understood thatthe privilege is reserved of resorting to all such legitimate changes inthe form, construction and relative arrangement of the several elementsas may be fairly considered within the spirit and scope of the inventionas claimed.

I claim:

1. In a centrifugal separator, having a horizontally positionedcylindrical Ascreen receiving stock under pressure, and revoluble meanstherein directing the stock under centrifugal force against the screenwall; means external to the screen receiving the screened stock at thetop of said screen and directing the same downwardly through a dischargeoutlet below said screen.

2. In a centrifugal separator, having a horizontally positionedcylindrical screen receiving stock under pressure, and revoluble meanstherein directing the stock under centrifugal force against the screenwall; a stock supply trough above the screen connected with one endthereof by a feed inlet, a discharge outlet for the residuecommunicating with the opposite end of said screen at the top thereofand extending upwardly to a receiving trough, and spaced cylinderssurrounding said cylindrical screen, the inner cylinder having anopening at the top thereof through which the screened stock passes intothe space between said cylinders, and said outer cylinder at the bottomthereof having an opening through which the screened stock is dischargedfrom said space.

3. In a centrifugal separator, a horizontally positioned cylindricalscreen, a revolubly mounted shaft extending through said screen, a hubfixed to said shaft within the screen, a plurality of radially disposedblades on one end of said hub, a stock feed inlet opening into one endof said screen, and an additional series of blades on the other end ofsaid hub extending from the shaft to a point closely adjacent to theinner surface of the screen.

4. A centrifugal separator as described in claim 3 in which saidadditional series of blades extend into the stock feed inlet to producerotary motion of the stock prior to its admission into the screen.

5. In a centrifugal separator, having a horizontally positionedcylindrical screen receiving stock under pressure, and revoluble meanstherein directing the stock under centrifugal force against the screenwall; means external to the screen receiving the screened stock at thetop of said screen and directing the same downwardly through a dischargeoutlet below said screen, said last mentioned means comprisingconcentrically spaced cylinders surrounding said screen, said innercylinder having an opening at the top thereof through which the screenedstock passes into the space between said cylinders, and said outercylinder having an opening at its lower side for the downward dischargetherethrough of the screened stock.

6. In a centrifugal separator, a horizontally positioned screen, feedingmeans for feeding stock under pressure to the interior of said screenadjacent the axis thereof, revoluble means in said screen for directingthe stock under centrifugal force against the screen wall, and outletmeans external tc the screen receiving the screened stock at the top ofsaid screen. and directing the same downwardly through a dischargeoutlet below the screen.

JOSEF KLOTZ.

